sample: invert the input string
by sii_side
HTML
<input onchange="hanten(this);">
JavaScript
function hanten(E) {
var A, AA, B, i;
A = E.value;
AA = A.length;
B = ""
for (i = 0; i <= AA; i++) {
B += A.charAt(AA - i);
}
E.value = B;
}